JP2021121263A - Balancer device - Google Patents

Abstract

To provide a balancer device which can be used in a state of being similar to a healthy knee state.SOLUTION: An inside body part which is provided on a femur side at inside of a knee is provided in a protruded state outward from an inside arm part 3b, and an outside body part which is provided on a femur side at outside of a knee is provided in a protruded state outward from an outside arm part 4b. The inside arm part and the outside arm part are extended in a front-rear direction of a knee at inside of a center in an inner-outer direction of a knee. A tibia arm part 2b provided on a tibia side body part 2a provided on a tibia side between the femur and the tibia is provided between an inside end of the inside arm part and an outside end of the outside arm part in the inner-outer direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a balancer device used between the femur and tibia to place an artificial knee joint.

Conventionally, as a balancer device used when installing an artificial knee joint, a tibia attachment part, a femur attachment part, and a femur attachment part are rotatably supported and vertically with respect to the tibia attachment part. Those having a moving mechanism for moving are known (see, for example, Patent Document 1). With this balancer device, the tibial attachment is attached to the proximal end face of the tibia, and with the tibial attachment pressed against the proximal end face of the tibia, the femur attachment is brought into contact with the distal end face of the femur and the femur. Gradually move the attachment part away from the tibia attachment part and move the femur attachment part away from the tibia attachment part so that the tension state (tension and left-right balance) of the ligament between the femur and tibia becomes a predetermined load. To adjust. At this time, it is configured so that it can be confirmed whether or not the proximal end face of the tibia and the distal end face of the femur are parallel by the rotating portion to which the femur attachment portion is fixed.

The femur is supported by two curved protrusions at the base of the knee that are spaced inward and outwardly apart, and when the femur attachment is moved away from the tibial attachment, the ligaments located on the medial and lateral sides of the knee The ligaments located on the back of the knee become tense. At this time, the tension of the ligament between the femur and the tibia can be determined by simply moving the femur attachment part away from the tibia attachment part and arranging the proximal end face of the tibia and the distal end face of the tibia in parallel. It is difficult to achieve proper tension on the inside and outside of the tibia.

In addition, as a conventional balancer device, a first adjustment plate placed between the femur and the tibia and in contact with the excised proximal tibia and the femur excised inside or outside the knee. Also known is an instrument (balancer device) that has two second adjustment plates that come into contact with each other and has a tensioner that independently extends the distance between the first adjustment plate and each second adjustment plate. (See, for example, Patent Document 2). This balancer device is placed in front of the knee to be treated and at a position facing the knee, and the first adjustment plate and the second adjustment plate are inserted between the femur and the tibia from the front of the knee for use. It is configured to be.

JP-A-2017-80569 Japanese Unexamined Patent Publication No. 8-229558

The balancer device is a femur and tibia that balances the tension of each ligament and applies an appropriate load so that the state of a healthy knee joint can be reproduced more accurately when an artificial knee joint is installed. It is desirable to be able to measure the distance between and. Furthermore, in order to more appropriately measure the distance between the femur and the tibia, the relative positions of the femur, tibia, each ligament, and the patella are measured in the same arrangement as in a healthy state. Is desirable. However, in the above-mentioned conventional balancer device, since the first adjustment plate and the second adjustment plate are inserted between the femur and the tibia from the front of the knee, the patella should be placed in front of the knee for use. There is a problem that more accurate measurement cannot be performed.

The present invention has been made in view of such a problem, and a main object thereof is to provide a balancer device that can be used in a state closer to a healthy knee state.

The main invention for achieving the above object is a balancer device used between the femoral bone and the tibia for installing an artificial knee joint, and the device main body and the tibia fixed to the device main body. A tibial side arrangement located on the proximal end side of the tibia, a medial tibial arrangement located between the tibial side arrangement and the distal end of the femur and inside the knee, and the medial femoral side arrangement. The lateral tibial arrangement, which is located between the tibial side and the distal end of the tibia and is located on the outside of the knee, and the medial tibial arrangement are connected to the tibial arrangement. The medial moving body movably provided with respect to the device main body in order to change the distance from the medial femoral side arrangement portion and the lateral femoral side arrangement portion are connected, and the tibia side arrangement portion and the lateral side are connected. A balancer device including a lateral moving body movably provided with respect to the device main body in order to change the distance from the tibial side placement portion, and the tibial side placement portion has one end of the device main body. The tibial arm portion fixed to the portion and the tibial side main body portion provided at the other end of the tibial arm portion and arranged on the tibial side are provided, and one end of the medial femoral side arrangement portion is said. It has an inner arm portion connected to the medial moving body and a medial body portion provided at the other end of the medial arm portion and arranged on the tibia side, and the lateral tibia side arrangement portion has one end. Has an outer arm portion connected to the lateral moving body and an outer body portion provided at the other end of the outer arm portion and arranged on the tibia side, and the medial body portion is the medial arm. The balancer device is characterized in that the outer main body portion is provided so as to project outward from the outer arm portion.
Other features of the present invention will be clarified by the description in the present specification and the accompanying drawings.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a balancer device that can be used in a state closer to that of a healthy knee.

It is a perspective view which shows the balancer apparatus of this embodiment. It is a side view which shows the state which the tibia contact part, the medial femur contact part, and the lateral femur contact part are inserted between the tibia and the femur trial after excision. FIG. 2 is a cross-sectional view taken along the line AA in FIG. It is a top view of the balancer device which removed the medial femur contact part and the lateral femur contact part. It is a top view of the balancer device. It is a top view which shows the central display part. FIG. 7 (a) is a perspective view showing a balancer device installed between the tibia and the femur, and FIG. 7 (b) is a perspective view showing a balancer device in a state where a rod is attached. FIG. 7 (c) is a perspective view showing a balancer device in a state where the lateral femur contact portion is raised. It is a side view which shows the state which the tibia contact part, the medial femur contact part, and the lateral femur contact part are inserted between the tibia and the femur after excision. It is a side view which shows the state which the tibia contact part, the medial femur contact part, and the lateral femur contact part are inserted between the tibia after excision and the femur after excision. It is a front view which shows the tilt display part. It is a top view which shows the tilt display part.

At least the following matters will be clarified by the description of this specification and the accompanying drawings. That is, it is a balancer device used between the femoral bone and the tibia for installing the artificial knee joint, and is fixed to the device main body and the device main body and arranged on the proximal end side of the tibia. The tibial side arrangement, the medial tibial arrangement located between the tibial side arrangement and the distal end of the tibia and inside the knee, and the tibial side arrangement and the tibial bone. The lateral femoral side arrangement, which is located between the distal ends and is located on the outside of the knee, and the medial femoral side arrangement are connected, and the tibial side arrangement and the medial femoral side arrangement are The medial moving body movably provided with respect to the device main body portion in order to change the interval and the lateral femoral side arrangement portion are connected, and the distance between the tibial side arrangement portion and the lateral femoral side arrangement portion is adjusted. A balancer device including an lateral moving body that is movably provided with respect to the device main body to be changed, and the tibial side arrangement portion is a tibial arm portion whose one end is fixed to the device main body. A medial arm having a tibial side main body provided at the other end of the tibial arm portion and arranged on the tibial side, and one end of the medial tibial arm portion connected to the medial moving body. It has a portion and a medial body portion provided at the other end of the medial arm portion and arranged on the tibia side, and one end of the lateral tibia side arrangement portion is connected to the lateral moving body. It has an outer arm portion and an outer main body portion provided at the other end of the outer arm portion and arranged on the tibia side, and the inner main body portion projects outward from the inner arm portion to extend the outer main body. The portion is a balancer device characterized in that the portion is provided so as to project outward from the outer arm portion.

According to such a balancer device, the medial femur side arrangement portion arranged on the medial side of the knee on the femur side and the lateral femur side arrangement portion arranged on the lateral side of the knee on the femur side are independent of each other. The vertical position, that is, the distance from the tibial side arrangement portion can be changed. Therefore, it is possible to set the distance to the tibia separately for the medial portion and the lateral portion of the femur. Therefore, according to this balancer device, the distance between the medial femoral side arrangement part and the lateral femur side arrangement part and the tibial side arrangement part, and the balance of the tension force by each ligament between the medial and lateral sides of the knee are appropriate. Can be in a state.

At this time, the tibial side main body is arranged on the tibial side between the femur and the tibia, the medial main body is arranged on the femur side, inside the knee, and the lateral main body is placed on the outside of the knee. It is possible to arrange the tibial arm, the medial arm, and the lateral arm medially from the central position in the medial-lateral direction of the knee while keeping them in contact with each other. That is, since the inner main body part protrudes outward from the inner arm part and the outer main body part protrudes outward from the outer arm part, the inner and outer main body parts are all offset from the extension line of each arm part, so that the femur. Since the front side of the femur and the tibia is vacant while the tibial side main body, the medial main body, and the lateral main body are arranged between the bone and the tibia, the tibial side main body, the medial main body, and When inserting the lateral main body, the patella once moved to the outside of the knee can be placed back in front of the femur and tibia. Therefore, it is possible to use the balancer device in a state closer to that of a healthy knee.

Further, the balancer device preferably has the following configuration. That is, it is desirable that the tibial arm portion is provided between the medial end of the medial arm portion and the lateral end of the lateral arm portion in the medial-lateral direction of the knee.
With such a balancer device, the entire tibial arm, medial arm, and lateral arm can be more reliably placed medially than in front of the knee.

Further, in the balancer device, it is desirable that the inner arm portion and the outer arm portion are arranged close to each other.
According to such a balancer device, the width occupied by the medial arm portion and the lateral arm portion in the left-right direction is narrowed, so that the tibial side main body, the medial main body, and the lateral main body are between the femur and the tibia. It is possible to leave a wider space on the anterior side of the femur and tibia when the is placed.

Further, in this balancer device, the angle formed by the device main body portion and the tibial side arrangement portion can be 95 degrees to 100 degrees.

The rough surface of the tibia protrudes anteriorly (anterior side in the depth direction) than the anterior side of the proximal end of the tibia. Therefore, when the balancer device is used, the main body of the device may come into contact with the rough surface of the tibia. At this time, when the angle formed by the device main body portion and the tibial side arrangement portion is 90 degrees, it is necessary to lengthen the tibial arm portion, the medial arm portion, and the lateral arm portion in order to avoid the rough surface of the tibia protruding forward. be. However, if the tibial arm, medial arm, and lateral arm are lengthened, the moment acting to increase the distance between the tibial side arrangement and the medial femoral side arrangement and the lateral femur side arrangement increases, so that the tibia The cross section must be large to ensure the rigidity of the arm, inner arm and outer arm. As a result, the amount of incision in the skin must be increased, the time until complete healing becomes longer, and there is a risk of developing an infectious disease.

On the other hand, as in this balancer device, the angle between the main body of the device and the tibial side arrangement is set to 95 to 100 degrees, so that the tibial arm and the medial side can be avoided while avoiding the rough surface of the tibia that protrudes anteriorly. It is possible to shorten the arm portion and the outer arm portion. Therefore, the tibial arm portion, the medial arm portion, and the lateral arm portion can be made thinner and shorter, and the amount of skin incision can be suppressed to be smaller.

Further, in the balancer device, the shape of the medial main body and the lateral main body arranged in the inner and outer directions and the shape of the tibial side main body are artificial when viewed from the femur side. It can be assumed that the shape is similar to the insert of the knee joint.

According to such a balancer device, the shape of the medial main body and the lateral main body combined and the shape of the tibial side main body are similar to the insert of the artificial knee joint. Therefore, it is possible to easily grasp the image when the insert is inserted and to obtain high reproducibility when the insert is inserted.

Further, the balancer device may have a central display portion indicating the central position of the knee on the tibial side in the medial-lateral direction.
According to such a balancer device, the tibial side main body portion that is inserted between the femur and the tibia and cannot be visually recognized, and the medial main body portion whose combined shape is similar to the tibial side main body portion. And the center position of the outer body can be confirmed by the center display. Therefore, the tibial side main body, the medial main body, and the lateral main body can be arranged at more appropriate positions.

Further, in the balancer device, the central display portion is provided on an extension line of a position forming a boundary between the inner main body portion and the outer main body portion in at least one of the inner moving body and the outer moving body. It is assumed that it has a central through hole penetrating in the front and back directions, and a rod that is inserted through the central through hole from the front side to the back side of the knee and projects toward the inner main body portion and the outer main body portion. be able to.

According to such a balancer device, the central display portion is composed of a central through hole provided in the inner moving body and the outer moving body and penetrating in the front and back directions, and a rod inserted through the central through hole and protruding. Therefore, not only the center position of the medial body and the lateral body can be confirmed by projecting the inserted rod, but also when the medial body and the lateral body are inserted between the femur and the tibia, the rod is inserted. By removing it, it is possible to immediately recognize the central position by simply inserting the rod after insertion without hindering the insertion of the inner main body and the outer main body.

Further, the balancer device has a moving mechanism for moving the medial moving body or the lateral moving body, and the moving mechanism arranges the medial femur side arrangement portion or the lateral femur side arrangement portion on the tibia side. A movement operation unit for moving in a direction away from the portion, a regulation mechanism for restricting the movement of the medial femur side arrangement portion or the lateral femur side arrangement portion in a direction approaching the tibia side arrangement portion, and the regulation. It is possible to have a release mechanism for releasing the above.

When the movement operation part is operated to move the medial femoral side arrangement part or the lateral femur side arrangement part away from the tibial side arrangement part by the movement mechanism, the medial femur side arrangement is performed against the tension of the ligaments. The part or lateral femoral placement part moves. Therefore, when a regulating mechanism for restricting the movement of the medial femur side arrangement portion or the lateral femur side arrangement portion in the direction approaching the tibia side arrangement portion is provided as in the balancer device, the movement is performed. Since the medial femoral side arrangement portion or the lateral femur side arrangement portion can be held at the moved position, operability is improved.

Further, in the balancer device, a grip portion capable of holding the device main body portion may be detachably provided on the device main body portion.

According to such a balancer device, since the grip portion capable of holding the device main body portion is provided, it is possible to easily operate the moving operation unit while holding the device main body portion by the grip portion. Further, since the grip portion is removable, the grip portion can be removed when it is not needed. Therefore, since the grip portion does not interfere with the operation during use and can be immediately attached when necessary, it is possible to provide a balancer device having further excellent operability.

Further, in the balancer device, the medial arrangement portion and the lateral arrangement portion are in contact with the bottom of the femur or the femur trial, and have a curved surface in which the central portion is recessed in the front and back directions. The curvature can be less than the curvature of the femur or the bottom of the femur trial.

According to such a balancer device, since the medial body portion and the lateral main body portion form a curved surface in which the central portion is recessed in the front and back directions, the femur or the femur that abuts in the flexed state and the extended state of the knee joint is formed. The point of contact with the trial can be located in the central recess. At this time, since the curvature of the curved surfaces of the medial body and the lateral body is smaller than the curvature of the bottom of the femur or the femur trial, the bottom of the femur or the femur trial is on the curved surfaces of the medial body and the lateral body. It is possible to rotate the femur smoothly while sliding. As described above, when the femur or the femur trial is stably arranged at a predetermined position on the curved surface of the medial main body and the lateral main body, the relative position with respect to the ligament does not change, so that it is more accurate. It is possible to use a balancer device by applying ligament tension.

Further, the balancer device may have an inclination display portion indicating the inclination of the femur or the bottom of the femur trial based on the movement of the medial moving body and the lateral moving body.

According to such a balancer device, the medial body located inside the knee at the bottom of the femur or femur trial and the lateral body located outside the knee at the bottom of the femur or femur trial. It is possible to visually recognize the inclination of the femur or the bottom of the femur trial simply by moving each of them by the moving mechanism and changing the distance from the main body on the tibial side.

Further, in the balancer device, the tilt display portion is provided on either one of the inner moving body and the outer moving body, and the first shaft portion along the front and back directions, the inner moving body and the outer moving body are provided. The second shaft portion provided on the other side of the body and along the front and back directions, and one end side rotatably provided on the second shaft portion, and the insertion hole provided on the other end side. It is possible to have an indicator needle through which the first shaft portion is inserted.

According to such a balancer device, the indicator needle whose one end side is rotatably provided on the second shaft portion has the first shaft portion inserted on the other side, so that the inner moving body and the outer moving body can be moved. It rotates due to a change in the relative position due to the movement of the body, and the inclination of the indicator needle itself changes. Therefore, it is possible to visually recognize the presence / absence and degree of inclination of the femur or the bottom of the femur trial by the inclination of the indicator needle.

Further, in the balancer device, the tilt display portion is locked to the inner moving body or the outer moving body provided with the second shaft portion, and the first shaft portion penetrates the first shaft through hole. The indicator main body has a scale indicating the inclination, and the indicator needle can rotate with the movement of the inner moving body and the outer moving body to point to the scale. ..

According to such a balancer device, the first shaft portion penetrating the display unit main body is provided on the inner moving body or the outer moving body together with the second shaft portion by the movement of the inner moving body and the outer moving body. Move relative to the main body. Therefore, it is possible to more accurately recognize the inclination of the bottom of the femur trial by the scale indicated by the indicator needle inclined by the movement of the medial moving body and the lateral moving body.
=== Embodiment ===

Hereinafter, a balancer device according to an embodiment of the present invention, that is, a balancer device used between the femur and the tibia for installing an artificial knee joint will be described with reference to the drawings.

The balancer device is used, for example, during total knee arthroplasty. In total knee arthroplasty, the patient's knee is first bent 90 degrees and the knee skin is incised to remove the damaged femur and tibia. A total knee arthroplasty is placed between the femur and tibia after excision. The artificial knee joint implant includes a tibial component provided at the excised part at the proximal end of the tibia, a femur component provided at the excised part of the femur, and an insert interposed between the tibial component and the femur component. Have. The balancer device, for example, removes the injured site of the femur in order to determine a size that provides an indication of the appropriate thickness of the insert inserted between the tibial component and the femur component. A femur trial (hereinafter referred to as the femur after excision) (a surgical instrument having the same shape as the above-mentioned femur component, which is used to reproduce the same joint condition as when the femur component was installed). Between the femur and the tibia after excision (hereinafter referred to as the tibia after excision) between the femur and the tibia after excision, as shown in FIG. , Inserted between the tibia after excision and the femur after excision and used to measure their spacing. In the present embodiment, a case where the distance between the femur trial attached to the femur and the tibia after excision is measured will be described as an example.

FIG. 1 is a perspective view showing the balancer device 1 of the present embodiment, and FIG. 2 is a side view showing a state in which the balancer device is inserted between the tibia and the femur trial after excision. In the following description, the direction in which the distance between the tibia T and the femur trial Fc after excision changes as measured by the balancer device 1 is the vertical direction, and the medial side of the patient's knee is simply medial and the lateral side of the knee is simply lateral. The left and right directions of the patient are the inward and outward directions that match each knee, and the front and back directions of the patient are the front and back directions that match the front and back of the knees, or the depth direction that is the front side or the back side when viewed from the practitioner side. It is explained as. Whether it is each part of the balancer device 1 or each member constituting the balancer device 1 is a single unit, the balancer device 1 is incorporated as the balancer device 1 in the vertical direction, the inner / outer direction, and the front and back directions. The direction will be specified and described in a direction such as a direction or a depth direction.

As shown in FIGS. 1 and 2, the balancer device 1 is used between the femur F and the tibia T, is arranged on the proximal end side of the tibia T, and comes into contact with the tibia T after excision. The medial femur abutment 3 and the lateral femur abutment 4 located between the tibia abutment 2 and the tibia abutment 2 and the distal end of the femur F and abutted by the femur trial Fc. A device main body portion 5 to which the tibia contact portion 2 is fixed, and a medial movement mechanism 6 and a lateral movement mechanism 7 for moving the medial femur contact portion 3 or the lateral femur contact portion 4 are provided. .. Here, the tibia contact portion 2 corresponds to the tibial side arrangement portion, the medial femur contact portion 3 corresponds to the medial femur side arrangement portion, and the lateral femur contact portion 4 corresponds to the lateral femur side arrangement portion. Equivalent to.

The balancer device 1 is used at the time of total knee arthroplasty of the left knee and at the time of total knee arthroplasty of the right knee, both in the tibia contact portion 2 and the medial femur contact portion. 3 and the lateral femur contact portion 4 are arranged so as to project outward from each knee with respect to the device main body portion 5. Therefore, in the balancer device 1 for the left knee and the balancer device 1 for the right knee, the tibia contact portion 2, the medial femur contact portion 3, and the lateral femur contact portion 4 are stretched against the device main body 5. The direction of ejection is reversed.

In the following description, the balancer device 1 for the left knee shown in FIG. 1 will be described as an example, but the balancer device 1 for the right knee projects to the outside of the right knee, that is, in the direction opposite to the left knee. Only the tibia contact portion 2, the medial femur contact portion 3 and the lateral femur contact portion 4 are replaced, and the configurations other than the contact portions 2, 3 and 4 are the same as those of the balancer device 1 for the left knee. be.

The device main body 5 has a shape in which the inner portion and the outer portion are symmetrical with respect to the center in the inner and outer directions. As shown in FIG. 3, the inner and outer portions of the device main body 5 are provided with moving body insertion holes 5a that penetrate substantially in the vertical direction and into which the inner moving body 60 or the outer moving body 70, which will be described later, is inserted. It has an inner tubular portion 5b and an outer tubular portion 5c arranged so as to be spaced apart from each other in the direction. An upper device main body 5d extending in the inner and outer directions is provided on the inner cylinder 5b and the outer cylinder 5c, and the upper ends of the inner cylinder 5b and the outer cylinder 5c are integrated with the upper device main body 5d. It is connected.

The moving body insertion holes 5a of the inner tubular portion 5b and the outer tubular portion 5c are provided at positions separated from the center of the device main body 5 in the inner and outer directions, and are connected to the upper surface 5e of the upper device main body 5d. Further, the upper device main body portion 5d, the inner cylinder portion 5b, and the outer cylinder portion 5c are connected to form the moving body insertion hole 5a. As shown in FIG. 1, the wall portion 5f on the front side of the device main body portion 5 is provided only with a portion from substantially the center to the lower side in the vertical direction, and the upper side has an open portion 5g open to the front side. ing. A guide 5h of the inner moving body 60 or the outer moving body 70 is provided on the inner / outer edge of the open portion 5g.

Further, on the inner side surface 5i of the inner cylinder portion 5b, the vicinity of the lower end portion of the outer side surface 5j of the outer cylinder portion 5c, and the wall portion 5f on the front side of the upper device main body portion 5d, there is a grip portion for holding the device main body portion 5. A screw mounting portion 5k capable of screwing 8 is provided. When the grip portion 8 is attached to at least one of the three screw attachment portions 5k to hold the balancer device 1, the operability is improved. In this embodiment, the screw mounting portion 5k is provided on the lower front side of the upper device main body portion 5d, on the left side of the inner cylinder portion 5b, and on the right side of the outer cylinder portion. Further, since the grip portion 8 in this embodiment is screwed, it can be easily attached, removed, and replaced as needed when operating the balancer device 1 or when performing a knee operation on the opposite side.

The inner moving mechanism 6 and the outer moving mechanism 7 are configured together with the device main body 5, and are guided by the respective moving body insertion holes 5a in the penetrating direction of the moving body insertion holes 5a by being operated from the outside. The inner moving body 60 and the outer moving body 70 are configured to be movable upward or downward along the line. Since the inner moving mechanism 6 and the outer moving mechanism 7 are partially different in arrangement but have the same configuration, the outer moving mechanism 7 will be described here as an example.

As shown in FIG. 3, the outer moving mechanism 7 is a regulating mechanism that regulates the descent of the rack 71 provided on the outer moving body 70, the pinion 72 that engages with the rack 71, and the outer moving body 70 that has moved upward. 73 and.

The outer moving body 70 is integrally provided on the shaft-shaped portion 70a and the shaft-shaped portion 70a that extends in the vertical direction and is movably inserted into the outer moving body insertion hole 5a, and is placed on the apparatus main body portion 5. It has a possible upper moving portion 70b.

The shaft-shaped portion 70a is provided with a rack 71 on the outer side surface from substantially the center in the vertical direction along the axial direction of the shaft-shaped portion 70a, and is provided on the inner side surface on the device main body portion 5 side. A plurality of regulating teeth 70c engaged with the regulating piece 74a and arranged side by side in the axial direction are provided from substantially the center to the upper side in the vertical direction.

As shown in FIG. 1, a flat projecting portion 70d is provided on the front side surface of the outer moving body 70 so that a portion substantially above the center in the vertical direction projects toward the front side to form a flat surface. The plane protruding portion 70d is configured to be arranged in the open portion 5g provided on the wall portion 5f on the front side of the device main body portion 5 in a state where the shaft-shaped portion 70a is inserted into the moving body insertion hole 5a. There is. The width of the plane protruding portion 70d in the inner and outer directions is formed to be slightly narrower than the width of the opening portion 5g in the inner and outer directions, and when the outer moving body 70 moves, the plane protruding portion 70d is formed by the opening portion 5g and the guide 5h. By being guided, the outer moving body 70 moves in a stable state.

Further, the plane protrusion 70d is provided with a scale 70e that can be visually recognized by the user of the balancer device 1. The scale 70e has the tibia contact portion 2 and the medial femur in a state where the upper moving portion 70b is placed on the device main body 5 and the lower surface of the upper moving portion 70b is in contact with the upper surface of the device main body 5. The height relationship (thickness) in the vertical direction with the contact portion 3 or the lateral femur contact portion 4 is shown. Then, when the lateral moving body 70 rises, the medial femur contact portion 3 or the lateral femur contact portion 4 and the femur trial are performed from the portion where the tibia contact portion 2 and the tibia T after excision are in contact with each other. The distance to the site where Fc is in contact is shown.

As shown in FIG. 3, the rack 71 engages with a pinion 72 provided on the lower end side of the outer tubular portion 5c of the apparatus main body portion 5. The pinion 72 is provided on the lower end side in the outer tubular portion 5c, and is rotatably provided around an axis along the front and back directions in a space communicating with the moving body insertion hole 5a. A hexagonal hole 72a having a hexagonal shape penetrating in the front and back directions is provided on the shaft of the pinion 72, and a hexagon wrench 9 or the like is inserted into the hexagonal hole 72a from the outside of the outer tubular portion 5c to rotate the pinion 72. It is configured to be possible. Here, the hexagonal hole 72a capable of rotating the pinion 72 corresponds to the movement operation unit.

The regulating mechanism 73 is provided on the upper side of the outer tubular portion 5c, and the regulating member 74 provided with the regulating piece 74a that engages with the regulating tooth 70c provided on the shaft-shaped portion 70a is urged outward by the spring 75. The regulatory piece 74a is configured to engage the regulatory tooth 70c. The regulating member 74 has a regulating projecting portion 74b that is integrated with the regulating piece 74a and projects to the outside of the outer tubular portion 5c. The regulation member 74 is configured to release the engagement between the regulation piece 74a and the regulation tooth 70c by pressing the regulation protrusion 74b inward and moving the regulation member 74 inward against the urging force of the spring 75. ..

On the outer side surface of the regulation piece 74a, that is, the side surface on the side that engages with the regulation tooth 70c, a plurality of claws 74c are provided, whose upper surface forms a horizontal plane and whose lower surface forms an inclined surface having a downward slope toward the inside. The regulating tooth 70c is provided with a plurality of grooves 70f whose upper surface forms an inclined surface having a downward slope inward and whose lower surface forms a horizontal plane in the vertical direction.

In the regulation mechanism 73, the claw 74c of the regulation piece 74a urged by the spring 75 is inserted into the groove 70f of the regulation tooth 70c in a state where the lower surface of the upper moving portion 70b is in contact with the upper surface of the device main body 5. The horizontal upper surface of the claw 74c of the regulation piece 74a and the horizontal lower surface of the groove 70f of the regulation tooth 70c face each other, and the inclined surface of the claw 74c of the regulation piece 74a and the inclined surface of the groove 70f of the regulation tooth 70c face each other. Therefore, the downward movement of the outer moving body 70 is restricted.

When the outer moving body 70 is pushed up by the pinion 72 that rotates by turning the hexagon wrench 9 inserted into the hexagonal hole 72a, the inclined surface of the groove 70f of the regulation tooth 70c rises and the inclined surface of the claw 74c rises upward. By pressing, the regulation piece 74a moves inward while moving along the inclined surface against the urging force of the spring 75. Then, when the claw 74c passes through the groove 70f, it is inserted into the groove 70f one level below by the urging force of the spring 75. That is, the movement of the outer moving body 70 in the ascending direction is permitted, but the movement of the outer moving body 70 in the descending direction is restricted. Therefore, it is possible to maintain the position of the outer moving body 70 at the pitch of the regulation teeth 70c. Therefore, it is desirable that the pitch of the regulation teeth 70c be the same as the scale 70e of the flat protrusion 70d.

The inner moving mechanism 6 has a substantially symmetrical shape in which the inner and outer directions are reversed from the outer moving mechanism 7, but the pinion 72 and the rack 71 are arranged on the same side as the outer moving mechanism 7. Therefore, the hexagonal hole 62a forming the movement operation unit of the inner movement mechanism 6 is also arranged on the same side as the outer movement mechanism 7. By arranging the hexagonal hole 62a of the medial movement mechanism 6 and the lateral movement mechanism 7 and the hexagonal hole 72a on the same side, the direction in which the pinion 62 should be turned in order to raise the medial femur contact portion 3 (right or left). And the direction (right or left) in which the pinion 72 should be turned in order to raise the lateral femur contact portion 4 are matched to enable intuitive operation and enhance operability.

As shown in FIG. 4, the tibia contact portion 2 has a tibia side main body 2a that comes into contact with the tibia T after excision and one end fixed to the device main body 5 in the front-back direction from the front side to the back side of the knee. It has a tibial arm portion 2b provided with a tibial side main body portion 2a at the other end extending to. The tibial side main body 2a has a shape similar to that of an artificial knee joint insert when viewed from the upper side, that is, the femur F side. The tibial arm portion 2b is arranged at a position that is significantly biased inward from the central position in the medial-lateral direction in the tibial side main body portion 2a, for example, near the medial end of the tibial side main body portion 2a. That is, the tibial arm portion 2b should be arranged in the center in the medial-lateral direction of the knee when the tibial side main body 2a is arranged between the femur F and the tibia T, in the medial-lateral direction in the tibial body 2a. It is placed in a position that is significantly biased inward from the center position of. Therefore, the tibial side main body portion 2a is set so that the amount of protrusion outward from the tibial arm portion 2b is larger than the amount of extension outward from the tibial arm portion 2b. The arrangement of the tibial arm portion 2b will be described in detail later.

As shown in FIG. 5, the medial femur contact portion 3 is arranged between the femur trial Fc provided at the distal end of the femur F and the tibial side main body portion 2a, and is the bottom of the femur trial Fc. An inner contact portion 3a that comes into contact with a portion located inside the knee in Fca, and an inner contact portion 3a that is connected to the medial moving body 60 at one end and extends in the front and back directions of the knee are provided. It has an inner arm portion 3b which is used. Here, the medial contact portion 3a corresponds to the medial main body portion provided at the other end of the medial arm portion 3b and arranged on the femur F side.

The lateral femur abutment 4 is located between the femoral trial Fc and the tibial body 2a and is located lateral to the knee in the bottom Fca of the femur trial Fc, similar to the medial femur abutment 3. The outer contact portion 4a that comes into contact with the portion to be contacted, and the outer arm portion 4b that is connected to the outer moving body 70 at one end and is provided with the outer contact portion 4a at the other end extending in the front and back directions of the knee. And have. Here, the lateral contact portion 4a corresponds to the lateral main body portion provided at the other end of the lateral arm portion 4b and arranged on the femur F side.

Here, as shown in FIG. 2, the bottom Fca of the femur trial Fc is a portion facing the tibia T when the knee joint is extended and flexed, and a protruding Fcb having a curved shape protruding downward is formed. Have. Two protrusions Fcb are provided at intervals in the medial and lateral directions of the knee. The medial contact 3a is in contact with the medial protrusion Fcb of the two protrusions Fcb of the bottom Fca of the femoral trial Fc, and the lateral contact 4a is of the bottom Fca of the femoral trial Fc. It is in contact with the protrusion Fcb located on the outer side of the two protrusion Fcb.

The medial contact portion 3a and the lateral contact portion 4a are arranged side by side in the inner and outer directions, and the state in which the medial contact portion 3a and the outer contact portion 4a are arranged side by side is viewed from the upper side, that is, the femur trial Fc side. The shape of the time is similar to the insert of the artificial knee joint. More specifically, it has a size that is arranged between the ligaments located on the medial and lateral sides, and the portion where the ligaments are arranged on the back side of the knee is provided with recesses 2c, 3i, and 4k that are curved toward the front side. The anterior side is sized to be placed inside the patella. The arranged medial contact portion 3a and lateral contact portion 4a are arranged on the tibial side main body portion 2a so as to overlap the tibial side main body portion 2a.

Further, as shown in FIG. 2, the angle θ between the device main body portion 5 and the tibia contact portion 2, the medial femur contact portion 3, and the lateral femur contact portion 4 is set to 95 degrees to 100 degrees. The tibia contact portion 2 is attached to the device main body portion 5, the medial femur contact portion 3 is attached to the medial moving body 60, and the lateral femur contact portion 4 is attached to the lateral moving body 70. More specifically, the angle θ formed by the lower surface of the tibia contact portion 2 and the moving direction of the medial moving body 60 and the lateral moving body 70, that is, the direction along the moving body insertion hole 5a is 95 degrees to 100 degrees. It is set. When this angle θ is 95 degrees or more, it is possible to prevent the device main body 5 from coming into contact with the tibial rough surface Ta of the tibia T protruding anteriorly from the femur F when the balancer device 1 is used. can. Since this angle θ is within 100 degrees, the angle between the device main body 5, the tibia contact portion 2, the medial femur contact portion 3, and the lateral femur contact portion 4 becomes too large, which improves operability. It is not inferior.

The upper surface of the medial femur contact portion 3 and the lateral femur contact portion 4, that is, the portion where the bottom Fca of the femur trial Fc abuts is provided with recesses 3c and 4c having curved surfaces R recessed downward, respectively. There is. More specifically, in the front-back direction of the knee, the front side portion 3d and 4d on the front side and the back side portion 3e and 4e on the back side have a curved surface whose central portion is lower than that on the back side. Further to the back side of the raised portions 3e and 4e, gradient portions 3f and 4f that gradually decrease toward the back end portion are provided.

Protrusions Fcb provided at the bottom Fca of the femur trial Fc are arranged in the recesses 3c and 4c of the medial femur contact portion 3 and the lateral femur contact portion 4, respectively, and during knee extension and flexion. The relative position of the femur F and the tibia T is maintained, and the normal state of the knee joint is reproduced. At this time, the curvature κ1 of the curved recesses 3c and 4c (= 1 / r1, r1 is the radius of curvature of the recesses 3c and 4c) is the curvature κ2 (= 1 / r2) of the protrusion Fcb of the bottom Fca of the femur trial Fc. , R2 is formed smaller than the radius of curvature of the protrusion Fcb), and the femur F and the tibia T rotate while the bottom Fca slides as in the case of extension and flexion of the knee, which is a normal knee. The state of the joint is reproduced.

As shown in FIGS. 4 and 5, the inner contact portion 3a projects outward from the inner arm portion 3b, and the outer contact portion 4a projects outward from the outer arm portion 4b, that is, the inner contact portion 3a and the outer offset. The contact portions 4a are all provided so as to be offset outward from the extension lines of the arm portions 3b and 4b. The center line of the medial contact portion 3a in the inward and outward directions of the knee is located outside the extension line of the medial arm portion 3b, and the center line of the lateral contact portion 4a is located outside the extension line of the outer arm portion 4b. Is preferable. As shown in the figure, it is preferable that both the inner contact portion 3a and the outer contact portion 4a project outward from the outer arm portion 4b. Further, it is preferable that the outer contact portion 4a exists only outside the extension line of the outer arm portion 4b. Further, the medial arm portion 3b and the lateral arm portion 4b are preferably located inside the center line of the tibial side main body portion 2a in the medial / lateral direction of the knee in the medial / lateral direction of the knee. Specifically, the extension line of the medial arm portion 3b is preferably located inside the center line of the tibial side main body portion 2a in the medial-lateral direction of the knee. Further, the extension line of the lateral arm portion 4b is preferably located inside the center line of the tibial side main body portion 2a in the medial-lateral direction of the knee. As a result, the inner arm portion 3b and the outer arm portion 4b extend inward of the center in the medial-lateral direction of the knee during the treatment.

The medial arm portion 3b extends toward the medial end 3g of the medial femur contact portion 3 and is connected in the vicinity of the medial end 3g. The front end of the inner arm portion 3b extends inward and forms an inner fixing portion 3h fixed to the inner moving body 60. The outer arm portion 4b of the lateral femur contact portion 4 has an inclined portion 4h extending medially and anteriorly from the front side portion on the inner side surface 4g of the lateral abutting portion 4a, and the front side of the inclined portion 4h. It has a front side extending portion 4i extending from the end of the front side to the front side along the front and back directions, and the end portion of the front side extending portion 4i extends outward, and the outer moving body 70. It forms an outer fixing portion 4j fixed to. As described above, the medial contact portion 3a projects outward from the medial arm portion 3b, and the lateral contact portion 4a projects outward from the lateral arm portion 4b. Since the front side of the femur and the tibia is vacant while 2a, the medial contact portion 3a and the lateral contact portion 4a are arranged, the tibial side main body portion 2a, the medial contact portion 3a, and the lateral contact portion When inserting 4a, the patella once moved to the outside of the knee can be placed back in front of the femur and tibia. Therefore, it is possible to use the balancer device in a state closer to the state of the knee before the treatment.

The medial arm portion 3b of the medial femur contact portion 3 fixed to the medial moving body 60 and the anterior extending portion 4i of the lateral arm portion 4b of the lateral femur contact portion 4 fixed to the lateral moving body 70. Are arranged so as to be close to the center in the inner and outer directions of the upper device main body 5d, and the inclined portion 4h of the outer arm portion 4b is placed on the back side of the knee so as to be along the front side portion of the inner contact portion 3a. The outer contact portion 4a is arranged so as to be located outside the inner contact portion 3a so as to extend toward the outside of the knee while facing the knee.

The medial contact portion 3a, the lateral contact portion 4a, and the tibial side main body 2a are viewed from above in a state where the lateral contact portion 4a is aligned outside the medial contact portion 3a and overlaps with the tibial side main body portion 2a. The shape at the time is similar to the insert of the artificial knee joint. Further, since the outer arm portion 4b is longer than the inner arm portion 3b, the moment when the tension force of the ligament acts becomes large. Therefore, the outer arm portion 4b is thicker than the inner arm portion 3b and is configured to have high rigidity. At this time, the reason why the inner arm portion 3b is not made thick like the outer arm portion 4b is to suppress the incision amount of the patient's skin at the time of the treatment to be smaller and to reduce the weight of the balancer device 1.

The tibial arm portion 2b of the tibial contact portion 2 arranged below the medial femur contact portion 3 and the lateral femur contact portion 4 is the medial edge 3j of the medial arm portion 3b of the medial femur contact portion 3. It is provided between and the outer edge 4l of the outer arm portion 4b of the lateral femur contact portion 4. In the present embodiment, the tibial arm portion 2b has a shape in which the medial arm portion 3b of the medial femur contact portion 3 and the anterior extension portion 4i of the lateral arm portion 4b of the lateral femur contact portion 4 are combined. It has an approximate shape. Here, the tibial arm portion 2b is larger than the combined size of the medial arm portion 3b and the lateral arm portion 4b if it is between the medial edge 3j of the medial arm portion 3b and the outer edge 4l of the lateral arm portion 4b. It doesn't matter if it is thin.

Further, the boundary portions between the adjacent inner contact portions 3a and the outer contact portions 4a are close to each other, and are configured to be located at the center of the knee in the inner and outer directions. On the other hand, since the boundary position between the medial arm portion 3b and the lateral arm portion 4b is located significantly inside the central position of the knee, the medial contact portion 3a, the lateral contact portion 4a, and the tibial side main body portion 2a Is inserted between the femur trial Fc and the tibia T after excision, the boundary position between the medial contact portion 3a and the lateral contact portion 4a becomes invisible. Therefore, as shown in FIG. 6, the balancer device 1 is provided with a central display unit 76 that indicates the central position (boundary position) of the inner contact portion 3a and the outer contact portion 4a.

The central display portion 76 of the present embodiment is provided on the medial moving body 60 and the lateral moving body 70 to which the medial femur contact portion 3 and the lateral femur contact portion 4 are attached, and the medial contact portion in the attached state. It is an extension of the straight line L that is the boundary between the contact portion 3a and the outer contact portion 4a, and is provided on the upper moving portions 60b and 70b of the moving bodies 60 and 70, and the inner fixing portion 3h and the outer fixing portion 4j. It is composed of central through holes 66a and 76a and rods 76b inserted through the central through holes 66a and 76a. That is, the central positions of the inner contact portion 3a and the outer contact portion 4a are pointed out by the direction in which the rod 76b inserted through the upper moving portion 70b is directed.

At this time, in the balancer device 1 for the left knee and the balancer device 1 for the right knee, the medial and lateral directions of the knee are opposite to each other, and the tibia contact portion 2, the medial femur contact portion 3, and the lateral femur contact portion Since No. 4 projects on opposite sides to each other, the central through holes 66a and 76a located on the outside according to the knee to be treated are used as the central display portion 76. At this time, by forming the rod into an L shape and making the tip into a hexagon wrench shape as shown in the figure, the medial femur contact portion 3 and the lateral femur contact portion 4 and the like can be attached and the pinion 72. It can also be used as an operation tool for. For example, if the balancer device 1 has a specification dedicated to the left knee or a dedicated right knee, the central display unit 76 does not necessarily have to be provided at two locations, but may be provided at only one of them.

Next, a method of measuring a value that serves as a guideline for an appropriate thickness of an insert in an artificial knee joint to be attached to a patient using the balancer device 1 will be described by taking the left knee as an example.
First, with the patient's knee bent 90 degrees, the skin of the left knee is vertically incised to expose the patella (not shown), and the patella is moved to the outside of the knee.
Next, the injured part of the tibia T is excised, the injured part of the femur F is excised, and the femur trial Fc is attached to the far end position.

Next, with the knee bent at about 90 degrees, between the femur trial Fc and the tibia T after excision, the tibial side main body 2a, the medial contact 3a, and the lateral contact 4a of the balancer device 1 To insert. At this time, as shown in FIG. 7A, the medial contact portion 3a and the lateral contact portion 4a of the balancer device 1 descend to the tibial side main body portion 2a side most. In addition, in FIG. 7A, FIG. 7B, and FIG. 7C, the femur F, the femur trial Fc, the tibia T, and the patella are omitted. In the present embodiment, the medial contact portion 3a and the lateral contact portion 4a are inserted in a state of being in contact with the tibial side main body portion 2a in the vertical direction facing each other, and the inserted tibial side main body portion 2a and the medial contact portion. The contact portion 3a and the outer contact portion 4a are arranged so that the protrusion Fcb of the femoral trial Fc is located in the recesses 3c and 4c of the medial contact portion 3a and the outer contact portion 4a.

Next, the patella that has been moved outward is returned to its original position. The returned patella is the outside of the tibial arm portion 2b, the medial arm portion 3b, and the lateral arm portion 4b, and is formed by the tibial side main body 2a, the medial contact 3a, the lateral contact 4a, and the device main body 5. Placed in between. At this time, as shown in FIG. 7B, the rod 76b is inserted through the outer central through hole 76a, and the inserted tibial side main body portion 2a, the medial contact portion 3a, and the lateral contact portion 4a are of the knee. Make sure it is in the center position.

Next, as shown in FIG. 7C, a hexagon wrench 9 is inserted into the hexagonal hole 72a and the pinion 72 is rotated to either the tibial side main body portion 2a and the medial contact portion 3a or the lateral contact portion 4a. Widen the distance between the heels. More specifically, the hexagonal hole 72a is rotated by using a torque driver 10 to which the hexagonal wrench 9 is attached to the hexagonal hole 72a. At this time, the torque driver 10 is set to a desired torque, the torque driver 10 is turned, and the operation of turning the torque driver 10 is stopped when the torque driver 10 idles beyond the set torque. This operation puts the ligaments in the desired tension. At this time, since the descent of the medial femur contact portion 3 or the lateral femur contact portion 4 is regulated by the regulation mechanism 73, the tibial side main body portion 2a and the medial contact portion 3a or the lateral contact portion 4a are combined. The interval is maintained.

After adjusting the distance between the tibial side main body portion 2a and the medial contact portion 3a and the lateral contact portion 4a so that the ligament exerts a desired tension force, the ligament is provided on the planar protruding portion 70d of the lateral moving body 70. By reading the scale 70e provided, a value that serves as a guide for the appropriate thickness of the insert in the artificial knee joint to be attached to the patient is recognized.

After reading the scale 70e, the regulation protrusion 74b is pressed inward to release the engagement between the regulation piece 74a and the regulation tooth 70c, and the inner contact portion 3a and the outer contact portion 4a are lowered to lower the balancer device. Remove 1.

According to the balancer device 1 of the present embodiment, the medial femur contact portion 3 arranged inside the knee on the femur F side and the lateral femur contact portion 3 arranged on the outside of the knee on the femur F side. Each of the 4 can independently change the position in the vertical direction, that is, the distance from the femur contact portion 2. Therefore, it is possible to set the distance between the medial portion and the lateral portion of the femur F and the tibia T separately. Therefore, according to the present balancer device 1, the distance between the medial contact portion 3a and the lateral contact portion 4a and the tibial side main body portion 2a is appropriately balanced between the medial and lateral sides of the knee and the tension force of each ligament. Can be in a state.

At this time, the tibia side main body portion 2a is arranged on the tibia T side between the femur F and the tibia T, and the medial contact portion 3a is arranged on the femur F side and inside the knee. While the lateral contact portion 4a is arranged on the outer side of the knee, the tibial arm portion 2b, the medial arm portion 3b, and the lateral arm portion 4b can be arranged on the medial side of the front surface of the knee. That is, the front side of the femur F and the tibia T is vacant while the tibial side main body portion 2a, the medial contact portion 3a, and the lateral contact portion 4a are arranged between the femur F and the tibia T. Therefore, when inserting the tibial side main body 2a, the medial contact 3a, and the lateral contact 4a, the patella once moved to the outside of the knee is placed back in front of the femur F and the tibia T. It is possible to do. Therefore, it is possible to use the balancer device 1 in a state closer to that of a healthy knee.

Further, since the medial contact portion 3a projects outward from the medial arm portion 3b and the lateral contact portion 4a projects outward from the lateral arm portion 4b, the tibial arm portion 2b, the medial arm portion 3b, and the lateral side The arm portion 4b can be more reliably arranged inside the front of the knee.

Further, in the balancer device 1, since the inner arm portion 3b and the outer arm portion 4b are arranged close to each other, the width occupied by the inner arm portion 3b and the outer arm portion 4b in the left-right direction becomes narrower. Therefore, when the tibial side main body portion 2a, the medial contact portion 3a, and the lateral contact portion 4a are arranged between the femur F and the tibia T, the front side of the femur F and the tibia T becomes wider. It is possible to leave it open.

The rough surface Ta of the tibia protrudes anteriorly (anterior side in the depth direction) than the proximal end of the tibia T. Therefore, when the balancer device 1 is used, the device main body 5 may come into contact with the tibial rough surface Ta. At this time, when the angle formed by the device main body 5 and the tibial side main body 2a is 90 degrees, the tibial arm portion 2b, the medial arm portion 3b, and the lateral arm portion are avoided in order to avoid the tibial rough surface Ta protruding forward. It is necessary to lengthen 4b. However, if the tibial arm portion 2b, the medial arm portion 3b, and the lateral arm portion 4b are lengthened, the moment acting when the distance between the tibial side main body portion 2a and the medial contact portion 3a and the lateral contact portion 4a is increased increases. Therefore, in order to secure the rigidity of the tibial arm portion 2b, the medial arm portion 3b, and the lateral arm portion 4b, the cross section must be enlarged. As a result, the amount of incision in the skin must be increased, in which case the time until complete healing becomes long and there is a risk of developing an infectious disease.

On the other hand, as in the balancer device 1, the angle formed by the device main body 5 and the tibial side main body 2a is set to 95 to 100 degrees, so that the tibial rough surface Ta protruding anteriorly is avoided and medial. The arm portion 3b and the outer arm portion 4b can be shortened. Therefore, the inner arm portion 3b and the outer arm portion 4b can be made thinner and shorter, and the amount of incision in the skin can be suppressed to be smaller.

Further, the shape of the medial contact portion 3a and the lateral contact portion 4a combined and the shape of the tibial side main body portion 2a are similar to the insert of the artificial knee joint. Therefore, it is possible to easily grasp the image when the insert is inserted and to obtain high reproducibility when the insert is inserted.

Further, since the balancer device 1 has a central display portion 76 indicating the central position of the tibial side main body portion 2a in the medial-lateral direction of the knee, the balancer device 1 is inserted between the femur F and the tibia T for visual recognition. The central display unit 76 confirms the center position of the tibial side main body 2a that cannot be used, and the medial contact portion 3a and the lateral contact portion 4a whose combined shape is similar to that of the tibial side main body 2a. It is possible. Therefore, the tibial side main body portion 2a, the medial contact portion 3a, and the lateral contact portion 4a can be arranged at more appropriate positions.
Further, the central display portion 76 is composed of a central through hole 76a provided in the inner moving body 60 and the outer moving body 70 that penetrates in the front and back directions, and a rod 76b that is inserted through the central through hole 76a and protrudes. Therefore, not only the central position of the medial contact portion 3a and the lateral contact portion 4a is confirmed by projecting the inserted rod 76b, but also the medial contact portion 3a and the lateral contact portion 4a are formed on the femur F or the femur. When inserting between the trial Tc and the tibia T, by removing the rod 76b, the insertion of the medial contact portion 3a and the lateral contact portion 4a is not hindered, and the rod 76b is immediately inserted after the insertion. It is possible to recognize the central position.

A direction in which the hexagonal hole 72a that rotates the pinion 72 is operated to separate the medial femur contact portion 3 by the medial movement mechanism 6 or the lateral femur contact portion 4 by the lateral movement mechanism 7 from the tibial side main body portion 2a. When moving to, the medial femur contact portion 3 or the lateral femur contact portion 4 moves against the tension of the ligament. Therefore, when the balancer device 1 is provided with a regulation mechanism 73 that regulates the movement of the medial femur contact portion 3 or the lateral femur contact portion 4 in the direction approaching the tibia contact portion 2. Since the moved medial femur contact portion 3 or the lateral femur contact portion 4 can be held at the moved position, the operability is improved.

Further, since the grip portion 8 capable of holding the device main body portion 5 is provided, the hexagonal hole 72a can be easily operated while holding the device main body portion 5 by the grip portion 8. Further, since the grip portion 8 is removable, the grip portion 8 can be removed when it is not needed. Therefore, since the grip portion 8 does not interfere with the operation during use and can be immediately attached when necessary, it is possible to provide the balancer device 1 having further excellent operability.

Further, since the medial contact portion 3a and the lateral contact portion 4a have recesses 3c and 4c forming a curved surface in which the central portion is recessed in the front and back directions, the femur that contacts the femur in the flexed state and the extended state of the knee joint. The point of contact with the bone F or the femoral trial Fc can be located in the central recesses 3c and 4c. At this time, since the curvature κ1 of the curved surfaces of the medial contact portion 3a and the lateral contact portion 4a is smaller than the curvature κ2 of the bottom Fca of the femur F or the femur trial Fc, the bottom Fca of the femur F or the femur trial Fc Can smoothly rotate the femur F or the femur trial Fc while sliding on the curved surfaces of the medial contact portion 3a and the lateral contact portion 4a. As described above, when the femur F or the femur trial Fc is stably arranged at a predetermined position on the curved surface of the medial contact portion 3a and the lateral contact portion 4a, the relative position with respect to the ligament changes. Therefore, it is possible to use the balancer device 1 by applying a more accurate ligament tension force.

In the above embodiment, an example in which the central display unit 76 is composed of the device main body portion 5 and the central through holes 76a and the rod 76b provided in the moving bodies 60 and 70 has been described, but the present invention is not limited thereto. For example, a protrusion protruding toward the knee side on an extension of a straight line L that is a boundary between the inner contact portion and the outer contact portion, or a boundary between the inner contact portion and the outer contact portion on the outer moving body 70. An extension line of the straight line L may be visibly provided.

In the above embodiment, the case of measuring the distance between the femur trial Fc attached to the femur F after excision and the tibia T after excision has been described as an example, but the present invention is not limited to this, and FIG. As shown, it is possible to excise only the tibia and measure the distance between the tibia T and the femur F after excision by the balancer device 1. At this time, the curvature κ1 of the curved recesses 3c and 4c is formed to be smaller than the curvature κ3 of the protrusion of the bottom Fa of the femur F. Further, by using the medial femur contact portion 3 and the lateral femur contact portion 4 in which the upper surfaces of the medial contact portion 3a and the lateral contact portion 4a are flat, as shown in FIG. 9, the tibia T after excision is used. It is also possible to measure the distance between the femur F and the femur F after excision.

As shown in FIGS. 10 and 11, the balancer device 1 shows the inclination of the bottom Fca of the femur trial Fc or the bottom Fa of the femur F that is in contact with the medial contact portion 3a and the lateral contact portion 4a. It is possible to attach the tilt display unit 12.

The inclined display unit 12 includes a first shaft portion 13 inserted into the central through hole 76a of the outer moving body 70, and a display unit main body 14 having a leg portion 14a inserted into the central through hole 66a of the inner moving body 60. A second shaft portion 15 provided on the display unit main body 14 and an indicator needle 16 rotatably supported by the second shaft portion 15 are provided.

The first shaft portion 13 is inserted into the central through hole 76a so as to project toward the front side in the depth direction. At this time, the first shaft portion 13 is immovably held by the outer moving body 70, and is attached with a slight margin so that it can be easily removed.

The display unit main body 14 includes a plate-shaped display plate portion 14b facing the wall portion 5f on the front side of the device main body portion 5, and leg portions 14a provided so as to project from the display plate portion 14b toward the back side in the depth direction. ,have. The leg portion 14a is immovably held by the inner moving body 60 when inserted into the central through hole 66a, and is attached with a slight margin so that it can be easily removed.

In a state where the leg portion 14a is inserted into the central through hole 66a, the display plate portion 14b is arranged at a distance from the wall portion 5f on the front side of the device main body portion 5 in the depth direction, and is locked to the inner moving body 60. Movement is restricted. At this time, the display plate portion 14b faces the inner moving body 60 and the outer moving body 70 at intervals in the depth direction.

A second shaft portion 15 that is concentric with the leg portion 14a is provided on the front surface of the display plate portion 14b, that is, the surface on the side opposite to the leg portion 14a. The second shaft portion 15 is provided on the front side along the depth direction. A first shaft through hole 14c through which the first shaft portion 13 inserted into the central through hole 76a penetrates is provided at a portion of the display plate portion 14b facing the outer moving body 70. Since the first shaft portion 13 moves together with the outer moving body 70, the first shaft through hole 14c forms a long hole that is long in the vertical direction, which is the moving direction of the outer moving body 70. Further, the display plate portion 14b is provided with a scale 14d pointed by the indicator needle 16 beside the first shaft through hole 14c.

The indicator needle 16 has a rotation hole 16a on which the second shaft portion 15 is rotatably inserted on one end side, and the first shaft portion 13 is rotatable and longitudinal on the other end side. An insertion hole 16b is provided which is an elongated hole that is movably inserted in a direction.

The tilt display unit 12 is in a state in which the upper moving portion 70b is placed on the device main body 5 and the lower surfaces of the upper moving portions 60b and 70b are in contact with the upper surface of the device main body 5, that is, the inner contact portion 3a. In a state where the lateral contact portion 4a faces the tibial side main body portion 2a and is in contact with the tibial side main body portion 2a, the indicator needle 16 points to the horizontal scale 14d as shown in FIG.

Then, by rotating the pinion 72 to widen the distance between the tibial side main body portion 2a and either the medial contact portion 3a or the lateral contact portion 4a, the indicator needle 16 is tilted, and the indicator needle 16 is varus or valgus. It points to the tilt angle of the opposite femur F.

According to the balancer device 1 provided with the tilt display portion 12 of the present embodiment, the medial contact portion 3a arranged inside the knee at the bottom Fca of the femur trial Fc or the bottom Fa of the femur F and the femur trial Simply move the lateral contact portion 4a located on the outside of the knee at the bottom Fca of the Fc or the bottom Fa of the femur F by the moving mechanisms 6 and 7, respectively, and change the distance from the tibial side main body 2a. , It is possible to visually recognize the inclination of the bottom Fca of the femur trial Fc or the bottom Fa of the femur F.

Further, since the indicator needle 16 having one end side rotatably provided on the second shaft portion 15 has the first shaft portion 13 inserted through the other side, the inner moving body 60 and the outer moving body 70 It rotates due to a change in the relative position due to movement, and the inclination of the indicator needle 16 itself changes. Therefore, it is possible to visually recognize the presence / absence and degree of inclination of the bottom Fca of the femur trial Fc or the bottom Fa of the femur F by the inclination of the indicator needle 16.

Further, the first shaft portion 13 penetrating the display unit main body 14 is provided on the inner moving body 60 or the outer moving body 70 together with the second shaft portion 15 due to the movement of the inner moving body 60 and the outer moving body 70. It moves relative to the main body 14. Therefore, it is possible to more accurately recognize the inclination of the bottom Fca of the femur trial Fc or the bottom Fa of the femur F by the scale 14d indicated by the indicator needle 16 inclined by the movement of the medial moving body 60 and the lateral moving body 70. It is possible.

Further, the above-described embodiment is for facilitating the understanding of the present invention, and is not for limiting and interpreting the present invention. It goes without saying that the present invention can be modified and improved without departing from the spirit thereof, and the present invention includes an equivalent thereof.

The present invention can be used when installing an artificial knee joint.

1 Balancer device 2 Tibial abutment 2a Tibial body 2b Tibial arm 2c Recess 3 Medial femur abutment 3a Medial abutment 3b Medial arm 3c Recess 3d Knee front side 3e Knee back Site 3f Slope 3g Medial end of medial femur contact 3h Medial fixation 3i Recess 3j Inner edge of inner arm 4 Outer femur contact 4a Outer femur 4b Outer arm 4c Recess 4d Front side of knee Part 4e The part on the back side of the knee 4f Gradient part 4g Inner side surface of the lateral femur contact part 4h Inclined part 4i Front side extension part 4j Outer fixing part 4k Indentation 4l Outer edge of outer arm 5 Device body part 5a Moving body insertion hole 5b Inner cylinder 5c Outer cylinder 5d Upper device main body 5e Upper surface 5f Wall 5g Opening part 5h Guide 5i Inner side 5j Outer side 5k Screw mounting part 6 Inner movement mechanism 7 Outer movement mechanism 8 Grip part 9 Hexagon wrench 10 Torque driver 12 Tib display 13 First shaft 14 Display body 14a Leg 14b Display plate 14c First shaft through hole 14d Scale 15 Second shaft 16 Indicator needle 16a Rotating hole 16b Insertion hole 60 Inside Moving body 60b Upper moving part 62a Hexagonal hole 66a Central through hole 70 Outer moving body 70a Axial part 70b Upper moving part 70c Control tooth 70d Plane protrusion 70e Scale 70f Groove 71 Rack 72 Pinion 72a Hexagon hole 73 Regulation mechanism 74 Regulatory piece 74b Regulatory protrusion 74c Claw 75 Spring 76 Central display 76a Central through hole 76b Rod F Femur Fa Femur bottom Fc Femur trial Fca Femur trial bottom Fcb Femur trial protrusion T Tibia Ta tibia Face Tc tibia trial

Claims (13)

A balancer device used between the femur and tibia to place an artificial knee joint.
The main body of the device and
A tibial side arrangement portion fixed to the device main body portion and arranged on the proximal end side of the tibia, and a tibial side arrangement portion.
A medial femur-side arrangement located between the tibial side arrangement and the distal end of the femur and inside the knee.
A lateral femur-side arrangement located between the tibial side arrangement and the distal end of the femur and outside the knee.
A medial moving body to which the medial femur side arrangement portion is connected and is movably provided with respect to the device main body portion in order to change the distance between the tibia side arrangement portion and the medial femur side arrangement portion.
A lateral moving body to which the lateral femur-side arrangement portion is connected and is movably provided with respect to the device main body portion in order to change the distance between the tibia-side arrangement portion and the lateral femur-side arrangement portion.
It is a balancer device equipped with
The tibial side arrangement portion has a tibial arm portion whose one end is fixed to the device main body portion and a tibial side main body portion provided at the other end of the tibial arm portion and arranged on the tibial side.
The medial femur-side arrangement portion includes a medial arm portion whose one end is connected to the medial moving body and a medial body portion provided at the other end of the medial arm portion and arranged on the femur side. Have and
The lateral femur-side arrangement portion includes a lateral arm portion whose one end is connected to the lateral moving body, and a lateral main body portion provided at the other end of the lateral arm portion and arranged on the femur side. death,
A balancer device characterized in that the inner main body portion is provided so as to project outward from the inner arm portion, and the outer main body portion is provided so as to project outward from the outer arm portion. The balancer device according to claim 1, wherein the tibial arm portion is provided between the inner end of the medial arm portion and the outer end of the lateral arm portion in the medial-lateral direction of the knee. The balancer device according to claim 1 or 2, wherein the inner arm portion and the outer arm portion are arranged close to each other. The balancer device according to any one of claims 1 to 3, wherein the angle formed by the device main body portion and the tibial side arrangement portion is 95 degrees to 100 degrees. The combined shape of the medial body and the lateral body arranged in the medial-lateral direction and the shape of the tibial body were similar to the insert of the artificial knee joint when viewed from the femur side. The balancer device according to any one of claims 1 to 4, wherein the balancer device has a shape. The balancer device according to any one of claims 1 to 5, further comprising a central display portion indicating the central position of the knee in the medial-lateral direction of the tibial side main body portion. The central display portion is provided on an extension line of a position forming a boundary between the inner main body portion and the outer main body portion in at least one of the inner moving body and the outer moving body, and the central display portion penetrates in the front and back directions. With a hole
A rod that is inserted into the central through hole from the front side to the back side of the knee and projects toward the inner main body and the outer main body.
The balancer device according to claim 6, wherein the balancer device has. It has a moving mechanism for moving the inner moving body or the outer moving body, and has a moving mechanism.
The movement mechanism includes a movement operation unit for moving the medial femur side arrangement portion or the lateral femur side arrangement portion in a direction away from the tibia side arrangement portion.
A regulatory mechanism that regulates the movement of the medial femur-side arrangement or the lateral femur-side arrangement in a direction approaching the tibia-side arrangement.
A release mechanism that releases the regulation and
The balancer device according to any one of claims 1 to 7. The balancer device according to any one of claims 1 to 8, wherein a grip portion capable of holding the device main body portion is detachably provided on the device main body portion. The medial and lateral arrangements are abutted against the femur or the bottom of the femur trial mounted on the femur.
Any of claims 1 to 9, wherein a curved surface having a central portion recessed in the front and back directions is formed, and the curvature of the curved surface is smaller than the curvature of the femur or the bottom portion of the femur trial. The balancer device described in. 6. Balancer device. The tilt display unit is
A first shaft portion provided on either one of the inner moving body and the outer moving body and along the front and back directions, and
A second shaft portion provided on the other of the inner moving body and the outer moving body and along the front and back directions, and
An indicator needle in which one end side is rotatably provided in the second shaft portion and the first shaft portion is inserted into an insertion hole provided in the other end side.
11. The balancer device according to claim 11. The tilt display unit is
A display unit main body having a first shaft through hole that is locked to the inner moving body or the outer moving body provided with the second shaft portion and through which the first shaft portion penetrates, and a scale indicating the inclination. With
The balancer device according to claim 12, wherein the indicator needle rotates with the movement of the inner moving body and the outer moving body to indicate the scale.

Images